Re: [asa] CO2 in Food Production...

From: Iain Strachan <igd.strachan@gmail.com>
Date: Mon Dec 07 2009 - 08:59:30 EST

The other aspect that John's trivia totally fails to address is that the
health benefit of cycling or walking will most likely lead to lower energy
usage.

When I started cycling to work in 2005, I was very overweight. I combined
cycling with being sensible about my diet (thus eating less straight off,
not more). Within 3 months I had lost 19 Kg of weight, so clearly I was
using significantly less energy to get myself around throughout the day. On
holiday in Paris late that summer I climbed up the first two stages of the
Eiffel tower with hardly any effort at all - just sailed up, whereas before,
it would have reduced me to a gasping heap.

Sadly, due to my weakness for food that's bad for me I have put much of it
back on since then, but that clearly wasn't to do with cycling - it was to
do with gluttony :-(

Iain

On Mon, Dec 7, 2009 at 1:10 PM, Merv Bitikofer <mrb22667@kansas.net> wrote:

> The trivia you mention below is a fallacy. From David McKay's "Sustainable
> Energy - Without All the Hot Air"
> (Book is available on-line)
>
> Here is an excerpt from his "Mythconceptions" section on p. 79:
>
>
> "I heard that the energy footprint of food is so big that its better to
> drive"
>
> Whether this is true depends on your diet. Its certainly possible to find
> food whose fossil-fuel energy footprint is bigger than the energy delivered
> to the human. A bag of crisps, for example, has an embodied energy of
> 1.4 kWh of fossil fuel per kWh of chemical energy eaten. The embodied
> energy of meat is higher. According to a study from the University of
> Exeter, the typical diet has an embodied energy of roughly 6 kWh per kWh
> eaten. To figure out whether driving a car or walking uses less energy, we
> need to know the transport efficiency of each mode. For the typical car
> of Chapter 3, the energy cost was 80 kWh per 100 km. Walking uses a net
> energy of 3.6 kWh per 100 km 22 times less. So if you live entirely on
> food whose footprint is greater than 22 kWh per kWh then, yes, the energy
> cost of getting you from A to B in a fossil-fuel-powered vehicle is less
> than
> if you go under your own steam. But if you have a typical diet (6 kWh per
> kWh) then its better to drive than to walk is a myth. Walking uses one
> quarter as much energy.
>
> <end of excerpt>
>
>
> ... and the "typical cars" he refers to are probably including European
> cars which are better on average then U.S. cars. Also, bicycling (I know
> this from personal experience) involves even less energy expenditure than
> walking or running. But of course, this is just the activity itself and
> doesn't take into account the carbon footprint of building the needed
> bicycle. But if we are to take production footprints into account then the
> car falls even more dismally behind. So bicycling probably has cars beat no
> matter how many hamburgers & cheese crisps you eat. Beating the auto
> transport industry's carbon footprint is like taking candy from babies. We
> would have to seriously try in order to be any worse. Shoot, --even loaded
> 747 jetliners can do it if the alternative was to put each driver into his
> own S.U.V. (which would nearly be typical here in the U.S.)
>
> --Merv
>
>
>
>
> John Walley wrote:
>
>> Here is an interesting tid bit of trivia I found while researching this.
>> Does anyone know if this has any basis to it or not?
>>
>> John
>> Here's a fun fact for you: If you live within walking distance of work,
>> which do you think would put more CO2 into the atmosphere, driving to work,
>> or walking to work? Contrary to what most would expect, the correct answer
>> is walking to work! The food production that would be necessary to replace
>> the calories that you would burn would put three times as much CO2 into the
>> atmosphere than driving your car the same distance! Thus, if you buy into
>> this global warming stuff, you better not exercise, because you are "causing
>> global warming!!"
>>
>>
>> To unsubscribe, send a message to majordomo@calvin.edu with
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>> ------------------------------------------------------------------------
>>
>>
>> Internal Virus Database is out of date.
>> Checked by AVG - www.avg.com Version: 8.5.426 / Virus Database:
>> 270.14.87/2534 - Release Date: 11/29/09 07:49:00
>>
>>
>>
>
>
> Internal Virus Database is out of date.
> Checked by AVG - www.avg.com
> Version: 8.5.426 / Virus Database: 270.14.87/2534 - Release Date: 11/29/09
> 07:49:00
>
>

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Received on Mon Dec 7 09:00:17 2009

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